WEEKVIII - June 30 - July 2

WEEK VIII

June 30

Installing drip irrigation system at the Terraces

Instead of digging the terraces and hooking up our own irrigation system to the main line, we decided to retrofit what we have. Already in place, there's a perimeter main line that runs all way around each one of the terraces. Each section has at least two pop-up riser sprinklers unevenly spaced, which makes a total of six irrigation heads to be replaced by header lines for drip irrigation. We decided to build six sub-headers that were butterfly shaped with tape opening into the sides of the beds. The sub headers will feed off of one of the emitter ports.

First we started by installing a stand-up pipe into the emitter (the original sprinkler was removed) and then we attached a sub-header that run crosswise through the bed. Coming of and perpendicular to the sub headers, we were able to attach the irrigation tapes. 

We used: 

• a 3/4 inch stand up 
• an elbow that we placed in the correct direction facing the beds and away from the wall

 

• a valve (for 3/4 inch pipe) that will allow us to control the water flow (turn on and off when not in use)

• a 15psi pressure regulator (at this point we don't know the pressure in this system yet, we also don't wanted to be too high with the drip system). When you buy tape it will tell you what psi works. Pressure regulators can only bring the pressure down, never up. Pressure regulator is almost a requirement with trickle irrigation systems, in order not to blow the line all the time. Particularly in farm use where farmers operate off wells, or out of irrigation ditches which are very variable sources and pressure could be all over the map. Even in the terraces, there can be spikes if one of the line plugs changing the total overall pressure of the system. Other kind of sprinkler in farms can be 70 or 150psi

•  A cross piece that will hold two drip tapes (one on each side) with on and off switches. We installed two cross pieces on each section.

• The cross pieces were connected with several pieces of PCVs (connectors). 
• Several end caps to place at the end of the tapes 

The sprinklers are unevenly spaced, nevertheless we were able to accommodate approx ten meters on each side of the  sub-header.

The first step to the installation was to measure how high we needed the risers, we aimed to have the elbow just below the height of the concrete, buried to prevent tripping accidents. 

Cutting the PVCs and assembling the irrigation arms:

1. Measure and cut 4 inches of PCV (this length varied across sections)

2. Cut two 3 inch section of PCV to connect the valve and the pressure regulator.

3. Cut two 1 foot of PVC to connect the first two cross pieces, and 3 feet to connect the next two across the path of the bed. 

We glued some of the pieces together at "the glueing station"

Last but not least, we added the irrigation tapes (sorry Mike I borrowed your picture, I had none of the end product, thank you). The same day, we run a few trials, adjusted a some minor details. With this system in place we will be able to reduce water consumption due to a significant reduction on water loss due to run of, wind, end evaporation. Another benefit is that foliage of plant will remain dryer, reducing the chances of crating the perfect environment for fungal disease.

We had a little guest today, he was found at the Sharing farm, its mom made a nest in one of the beds, she would not take the egg back once humans touch it. Oliver was successful at incubating the egg and voila! Good luck little fellow, we hope you make it.

July 2

The Terraces

Irrigation System Update

The puddles that were forming around the terraces from the old irrigation system are drying out, a sign that the new drip irrigation system is wasting less water. 

Some of the sprinklers are leaking, you find some because of their hissing noise, wetness or excess water accumulation around them, a big depression/soil eroded around it. The heads might need further adjustment with a screw driver, might need disassembling and cleaning as sometime sand particles impede proper closure and sealing, or might need to be replaced.

Some of the end caps were missing, maybe the water pressure blasted them off or they were not in place to begin with. A cap can be made also by cutting a piece of tape and using it as a cap to hold the end.

The Professional Gardener. Spacing the T-tapes into rows. Planting. Web. n.d.

Tunnel

• The microclimate is much warmer and humid in the tunnel. This causes the plants inside to be bigger than their same crop varieties (tomatoes, zucchini) planted outside. 

• There are a few aborted zucchinis that indicates there wasn't sufficient pollination, the plant started to produce a fruit but the fruit is not going to mature. There's also lots of fruit that are forming.

• We finally can use t-tape to put in between the plastic and the staple so it could hold on to the tow board, and avoid ripping the plastic. We can have more stable and stronger side walls and end doors once we anchor the plastic to the tow boards. Until now, the plants at the end are stressed as compared to the once in the middles of the tunnel because the plastic doors blow in and out with the wind. The weight of the tow board will keep the doors closed and in place.

• The tomatoes are tall enough to be trellised inside and outside the tunnel.

Beds

The basil is going to flower, they need to be pinched

The first zucchinis and cucumbers are almost ready to be harvest  (anything approx. 5 inches long)

A few weeks ago, we collected data on lettuce emergence and yield in the experimental plots. We found a significant difference between all our treatments in that first harvest with the control being the lowest yield, followed by the harvest power plot, and then the net zero compost having the highest yield. The difference in plant size is not that obvious with the swiss chard. Due to the fact that chard took longer to germinate and grow, it might have missed the initial effects of having high salt content or low nutrient  availability in the compost, factors that with time were washed out by constant irrigation/microbial activity, etc. These factors might have affected lettuce more directly.

Chard needed to be harvest and data collected on weight and number of plants, in order to calculate mean weight per plant. 

Removed arugula

Trimmed lambs quarter to avoid it going to seed